Troubleshooting For Each Symptom; I/O Operation (Cpu Module, I/O Module) - Mitsubishi Electric MELSEC iQ-F Series User Manual

15.7

Troubleshooting for Each Symptom

When the CPU module does not operate properly, check the appropriate item from the following and perform troubleshooting.

I/O operation (CPU module, I/O module)

Output does not turn on
Item to check
Check for errors with external wiring.
Stop the programmable controller, and forcibly turn on or off the inoperable
output with a peripheral or the engineering tool.
Output does not turn off
Item to check
Check for errors with external wiring.
Stop the programmable controller and check that the output turns off.
Input does not turn on
Item to check
Disconnect the external wiring and connect "the [S/S] terminal and the [0V]
terminal" or "the [S/S] terminal and the [24V] terminal".
Short-circuit the [0V] terminal or [24V] terminal not connected to the [S/S]
terminal and the input terminal, and check the LED or a peripheral to check
that the input turns on.
■For FX5UC-MT/D
Disconnect the external wiring and short-circuit the COM terminal and the
input terminal. Check with the LED or a peripheral whether the input turns on.
15 TROUBLESHOOTING
260
15.7 Troubleshooting for Each Symptom
Action
Connect the external wiring properly.
■When the output operates
The output may be turned off unintentionally in the program. Review user
program (Duplicate coils or RST instructions).
■When the output does not operate
Check the configuration of the connected devices and the connection of the
extension cables.
When the configuration of the external wiring and connected devices and the
connection of the extension cables are acceptable, there may be a hardware
issue. Consult your local Mitsubishi Electric representative.
Action
Connect the external wiring properly.
■When the output turns off
The output may be turned off unintentionally in the program. Review user
program (Duplicate coils or RST instructions).
■When the output does not turn off
There may be a hardware fault. Consult your local Mitsubishi Electric
representative.
Action
■When the input turns on
Check that the input device does not have a built-in diode or parallel
resistance. If so, refer to Page 178 Wiring precautions.
■When the input does not turn on
Measure the voltage between the [0V] terminal or [24V] terminal not
connected to the [S/S] terminal and the input terminal with a tester to check
that the voltage is 24VDC.
Check the configuration of the external wiring and connected devices and the
connection of the extension cables.
■When the input turns on
Check that the input device does not have a built-in diode or parallel
resistance.
If so, refer to the precautions for connecting input devices.
■When the input does not turn on
Disconnect the external wiring and measure the voltage between the COM
terminal and the input terminal with a tester to check that the voltage is
24VDC.
When the input voltage is below 20.4VDC, check that the power supply
voltage of the programmable controller is "24VDC +20%, -15%".
Check the configuration of the external wiring and connected devices and the
connection of the extension cables.